Flexible printer bar for electrical recorders



.June l, 195.4 -R. G. OLDN'- l 680,056 `FLEXIBLEPRINTER BARFORELECTRIQALRECORDERS 4` Filed June-2o, 1950v Patented June 1, 1954FLEXIBLE PRINTER BAR FOR ELECTRICAL RECGRDERS Roger G. lden, Princeton,N. J., assignor to Radio Corporation of America, a corporation ofDelaware Application June 20, 1950, Serial No. 169,103

6 Claims. l

This invention bears cn electrical recording means, namely, but notexclusively, on the aspect of this subject as it concerns a printer barfor cooperation with one or more helical electrodes.

In a chemical or similar recorder, a -drum is present having one or morehelical electrodes. lf' more than one helix is used, or if the printerbar touches a single helix at more than one point, it will then beobvious that a plurality of printing couples are present. lf both theprinter bar and the helix are rigidly mounted, it is impractical tomaintain their arrangement with such precision that the paper squeeze isconstant. The bar of this invention is particularly useful in carryingout recordings in accordance with methods, the chemistry of which is setforth in the Proceedings of the I. R. E. for October, 1948, vol. 36, No.l0, 1321.1224 to 1235.

A flexible printer bar of novel construction is provided which isflexible radially of the helix and stiffness laterally of the printerbar is provided by the combination of a novel holder With the bar. Theprinter bar of the invention is of relatively great depth so that alarge evaporating surface is provided for evaporating moisture picked upfrom the moistened recording medium. In a high speed recorder, therecording medium carries more liquid on its surface than in slow speedoperation so as to utilize the run between the moistened means and theprinting point for liquid penetration. This moisture may be evaporatedby a preheater prior to printing, but in the printing process heat isgenerated in the medium which vaporizes much of the moisture stillremaining in it. This vapor condenses on the relatively cool printer barand may collect in drops which will stain the medium. The greaterevaporating surface prevents accumulation of drops. Flexibility radiallyof the recording drum is provided in accordance with the invention by arelatively great number of sawcuts milled from the base of the printerbar. This compensates for the increase in stiffness caused by therelatively greater depth of the bar. The slots or saw-cuts promote freecirculation of air which assists in evaporating excess moisture on thebar. Lateral stiffness Which is impaired by theslots or saw-cuts isincreased by inserting the printer bar in the previously mentionedholder. While the connection of the printer bar to the holder is firm,lit permits expansion of the bar. Also,'in accordance with the invention,the bar is detachable from the holder.

The. principal object is to provide a combined printer bar and holder ofnovel construction.

A further object of the invention is to provide a novel printer barwhich is generally T-shaped in cross-section and is notched to impartflexibility.

Still another object of the invention is to provide a novel holder for aprinter bar in which the printer bar is removably secured.

Other objects will be seen by reading this specication which refers tothe drawing in which:

Figure 1 is a View in front elevation of the printer bar of thisinvention in conjunction with a recording or helix carrying drum;

Figure 2 is a view in cross-section on line 2-2 of Fig. 1;

Figure 3 is a fragmentary longitudinal sectional view taken on line 3-3of Fig. 2; and

Figure 4 is a fragmentary bottom plan view.

Referring for the present to Fig. 1 of the drawing, there is shown, byWay of example, a part of a recorder Which is suitable for marking inaccordance with facsimile signals. This recorder may be of the charactershown in U. S. Patent No. 2,215,806 granted to Charles J. Young onSeptember 24, 1940.

The recorder comprises a recording drum l2, provided with a helicalelectrode it mounted on its periphery which cooperates with a secondelectrode in the form of printer bar l5. The drum I2 may have additionalhelices (not shown). This printer bar member is carried by the novelholder of the present invention indicated generally by the referencecharacter i8.

The record sheet or paper web 25 which is threaded between the printerbar it and the electrode lf3 is drawn through the recording zone bysuitable means (not shown). The drum and paper feed means may be drivenin a coordinated manner by suitable means (not shown). Patent No.2,215,806 referred to above shows such means as Well as paper drivemeans. synchronizing and phasing signals may be generated andtransmitted as described in U. S. Patent No. 2,326,740 granted toMaurice Artzt on August 17, 1943, when desirable or necessary.

The printer bar I6 of the invention is or may be in effect a compositestructure comprising a resilient strip 32 to which is secured a metallicstrip 33. The latter is of relatively great depth as shown in thedrawing. The strip 32 is preferably of metal. The strip 33 is or may bejoined to the strip 32 by a series of spaced spot welds, or the Tsection may be formed from one piece. The strip 32 provides a base orflange and the projecting strip 33 is located substantially centrally onthis base. The free edge of the strip 33 provides a thin electrode edgefor cooperation with the helix. Reference character 38 indicates thechannel-shaped holder for the printer` bar. The holder 38 is cemented orotherwise secured to a yielding membrane 4l which spans a slot or recess3 in a supporting member 48. The supporting member 48 is shown as anelongated block and it may be secured at its end in any suitable manner,not shown, to stationary parts, such as end flanges of the recorder inwhich it is used.

As indicated in Fig. 3 of the drawing, the

entire printer bar l5, including the strip 32 and the top of the strip33, is provided with slots or saw-cuts i. These slots or saw-cuts extenddownwardly so that the part of the strip remaining as at 55 isrelatively narrow.

The holder 3B, stated above as being cemented to the membrane di, ischannel-shaped as shown in Fig. 2 of the drawing and comprises a flatelongated part 5G against which the strip 32 rests. This part alsoprovides the flat surface which is bonded by cement to the membrane 4l.Flanges 58 and 59 provide grooves at each side into which. the edges ofthe strip 32 fit when the printer bar l5 is slid into the holder 38.

As shown in Fig. 3, the strip 33 is slightly shorter than the strip 32so that the strip 32 has a slight overhang as indicated at t2. rhe part55 of the holder 38 is longer than the flanges 58 and 5S which providesa tongue portion Se which can be bent down to seat securely against theunderside of the overhang 52. When a printer bar SS is to be renewed,one of the tongues 64 may be bent upwardly so that the bar i5 may beslid out of the channel provided between the flanges 58 and 59 and a newbar may be slid into place.

It will be seen that the combination of the printer bar and novelprinter bar holder of this invention provides an arrangement whichsolves the problem of evaporation of excess liquid and also simplifiesremoval and renewal of the printer bar. Since only the holder 38 iscemented to the membrane lli, it is possible to remove worn bar andslide in a new bar in a matter of minutes. A further advantage of thebar of this invention resides in the fact that it can expand in theguide channel, when heated, without causing buckling.

What is claimed is:

l. In combination in facsimile apparatus, a rotary drum having a helicalmember supported thereon, an elongated printer bar arranged to bepositioned in cooperative relationship to the drum and helical member soas continuously to bring the bar and the helix to bear upon each other,a recessed support element for said printer bar, resilient meansspanning the recess in the support element, said printer bar being of Tshape and comprising a ilat ilange and a strip, the free edge of saidstrip providing a printing electrode, means for securing said ilange tosaid resilient means, and spaced slots extending from the edge of saidflange and continuing a substantial distance into said strip, the drumand the printer bar being adapted to receive a record receiving stripbetween them.

2. In combination. in facsimile apparatus, a rotary drum having ahelical member supported thereon, an elongated printer bar arranged tobe positioned in cooperative relationship to the drum and helical memberso as continuously to bringl the bar and the helix to bear upon eachother, a recessed support element for said printer bar, resilient meansspanning the recess in the support element, said printer bar being of Tshape and comprising a flat llange and a strip, the free edge of saidstrip providing a printing electrode, a holder secured to said resilientmeans, said flange being seated in said holder, and spaced slots in saidflange and said strip, said slots being in register whereby to extendcontinuously from the edge of said Ilange to a relatively short distancefrom the edge of said strip.

3. A printer bar for a facsimile recorder comprising a base in the formof a flange, and a strip projecting from said flange and beingsubstantially centrally located on said flange, the free edge of saidstrip providing a printing electrode, spaced slots in said ilange andstrip, said slots extending continuously from the edge of said ange towithin a relatively short distance from the edge of said strip, wherebysaid strip has a relatively shallow continuous portion adjacent saidedge which provides the printing electrede, said continuous portionbeing flexible transversely of its length in its plane.

fi. A printer bar for a facsimile recorder comprising a base in the formof a llange, and a strip integral with and projecting from said flangeand being substantially centrally located on said ilange, the free edgeoi said strip providing a printing electrode, spaced slots in saidflange and strip, said slots extending continuously from the edge cisaid flange to within a relatively short distance from the edge of saidstrip whereby said strip has a relatively shallow continuous portionadjacent said edge which provides the printing electrode. saidcontinuous portion being ilexible transversely of its length in itsplane.

5. A printer bar and printer bar support for a facsimile recordercomprising an elongated prin er bar having a projecting recording edge,a support for said bar comprising an elongated member having anelongated recess therein, a thin flexible strip secured to saidelongated member to cover said recess, a holder for said printer barcomprising a channel-shaped member having inturned sides slidably toreceive said printer bar, said printer bar being removably secured tosaid holder in alignment with and substantially centered with respect tosaid recess, and said holder being narrower than said recess.

6. A printer bar and printer bar holder for a facsimile recorder, saidprinter bar comprising a flange and a ilexible strip extending from saidilange, said holder comprising a flexible, unitary channel-shaped memberhaving a flat portion and inturned sides iltting beneath the flange ofsaid printer bar, said flat portion and said inturned sides providing achannel for slidably receivingr said printer bar, said flange of saidprinter bar extending beyond said strip at at least one end of saidprinter bar, and said ilat portion of said holder having a projectingportion turned inwardly over the projecting portion at the end of saidprinter bar flange.

References Cited in the ille of this patent UNITED STATES PATENTS NumberName Date 1,794,700 Mecaskey Mar. 3, 1931 2,223,680 Fischer et al. Dec.3, 1940 2,380,467 Ressler July 31, 1945 2,413,962 Finch Jan. 7, 19472,415,229 Young Feb. 4, 1947 2,495,271 Long Jan. 24, 19511

